The Hematology Research Training Program at the University of Pennsylvania was established in 1978 and currently supports 8 postdoctoral trainees per year. Since its inception 24 years ago, the goal of our program has been to identify individuals interested in the broadly-defined discipline of hematology, and to help them prepare for academic careers as independent investigators using their scientific training in basic, translational and patient-oriented research. Originally the candidates were drawn almost exclusively from physicians enrolled in the clinical hematology-oncology training programs in the Departments of Medicine and Pediatrics, but as specified at the time of the last renewal, we have deliberately sought non-physician postdoctoral trainees in order to provide a mix of backgrounds and interests. During the first 24 years of 'funding, 87 postdoctoral trainees and one pre-doctoral trainee have been supported: 63 M.D., 12 M.D.-Ph.D. and 12 Ph.D. Twenty five of the trainees are women and 63 are men. Of the 77 trainees who have completed training, 47 (61%) hold full-time appointments at an academic institution and are engaged in either laboratory or clinical research. An additional 7 (9%) are engaged primarily in clinical practice, but have university appointments and participate in clinical research projects and teaching part-time. Thirty four of our former trainees who have completed training have extramural research funding. Thirty nine hold faculty appointments at 24 institutions, including Penn, Harvard and the NIH. Although historically this program has supported postdoctoral trainees almost exclusively, we now seek added support in order to appoint up to 4 predoctoral trainees per year. These additional trainees will be drawn primarily from physician-scientist trainees in Penn's MD-PhD program - a program that is also directed by Lawrence Brass, the principal investigator on this grant. The addition of predoctoral students to our program reflects our belief in the long term value of attracting talented students in hematology-related research at an earlier point in their training. A detailed plan for identifying appropriate pre- and postdoctoral candidates, providing them with the research and laboratory skills needed for an independent career, and mentoring them throughout the process is included in the application.